If they are worm castings, and it sounds like they are, you are in luck. They will only enrich the soil and feed your tree. I'd gently rake some up and put them on other flower beds. Worm casting are black gold and people pay big bucks for them. Even consider starting a road side stand. All the Best And Happy Yardening, Nancy.
Pea Sized Dirt Mounds Erupting On Lawn
Question From: J. Bartz - WASHINGTON
Q: In a section of our lawn (approx 15' diameter), a strange phenomenon is perplexing us. It seems like 'the dirt is erupting upwards (in loose pea-size granules), enough to completely cover over the grass in many spots. This is far more severe/noticeable in the winter months (when grass growth is largely dormant). We live in Olympia, WA (sea-level elevation). This afflicted section of our lawn is 'under a Hawthorne tree'. It looks sort of like 'worm/nightcrawler dirt mounds', except larger and much more numerous. We do not think that it could be moles. It's 'as if thousands of giant nightcrawlers are pushing the dirt up' in this area. The dirt is very fertile. Any help will be greatly appreciated!